v3.26.1
Copper Mountain non-controlling interest acquisition (Schedule of detailed information about acquisition transaction) (Details) - USD ($)
$ in Millions
1 Months Ended 12 Months Ended
Apr. 30, 2025
Dec. 31, 2025
Disclosure of detailed information about business combination [line items]    
Surplus - recorded in equity   $ (35.9)
Copper Mountain Mine (BC) Ltd. [Member]    
Disclosure of detailed information about business combination [line items]    
Surplus - recorded in equity $ 61.3  
Copper Mountain Mine (BC) Ltd. [Member] | Mitsubishi Materials Corporation [Member]    
Disclosure of detailed information about business combination [line items]    
Carrying value of non-controlling interest as at April 30, 2025 93.2  
Transfer of net gain on translation of foreign currency balances 4.0  
Less: total consideration $ (35.9)